Diesel Engine

The 6.7L Diesel engine allows the turbocharger inlet pipes to transport the exhaust gas from the exhaust manifolds to the turbocharger. The expansion joint (bellows) in the turbocharger inlet pipes is to accommodate thermal growth in the turbocharger inlet pipes and is not an assembly aid. The turbocharger inlet pipe bellows should not be bent or twisted during removal or installation. The upper and lower exhaust downpipes deliver the exhaust gas from the turbocharger to the catalyst and particulate filter assembly.

The catalyst and particulate filter assembly OC is a ceramic catalytic converter which oxidizes hydrocarbons in the exhaust and generates heat for DPF regeneration. The DPF is a highly engineered silicon carbide wall-flow catalyst that traps particulates. As soot gathers in the system it begins to restrict the filter and the filter needs to be periodically cleaned. The soot can be cleaned in 2 different ways: Passive regeneration and active regeneration. Both methods occur automatically and require no action from the driver/operator.

The selective reduction catalyst improves the exhaust emissions and fuel efficiency by injecting a reductant into the exhaust system. The reductant, also referred to as diesel exhaust fluid, is a 32.5% solution of urea in deionized water. At the inlet of the catalyst, there is a port for the reductant injector which is followed by a grate diffuser and a twist mixer. When the reductant is introduced into the system, it atomizes in the grate diffuser and mixes evenly with exhaust gases in the twist mixer. During this time, the heat of the exhaust gases causes the urea in the reductant to split into Carbon Dioxide (CO2) and ammonia. As the ammonia and NOx pass over the catalyst, a reduction reaction takes place and the ammonia and NOx are converted to nitrogen and water. For additional information about the reductant system, refer to ENGINE EMISSION CONTROL .